IPv4 Network Calculator
Enter an IPv4 address and CIDR prefix to instantly calculate subnet mask, network ID, broadcast address, host range, and more.
/24, /16, /30How to Use This Network IP Address Calculator
This tool helps you quickly break down an IPv4 address into practical subnet details. If you are planning VLANs, configuring routers, documenting server ranges, or studying for networking certifications, this calculator saves time and reduces mistakes.
- Type an IPv4 address (like
10.20.30.40). - Enter the CIDR prefix (like
24for/24). - Click Calculate Network to get all core subnet values.
What the Results Mean
Network Address
The network address identifies the subnet itself. It is the first address in the block and cannot be assigned to a normal host device (except special use cases in point-to-point links).
Broadcast Address
The broadcast address is the last address in the subnet and is used to send traffic to all hosts in that subnet.
First and Last Usable Host
These values show the assignable host range for most subnets. For /31 and /32, special rules apply and the calculator displays that behavior automatically.
Subnet Mask and Wildcard Mask
The subnet mask defines which bits are network bits. The wildcard mask is the inverse of the subnet mask and is often used in ACLs and route filtering.
Quick CIDR Reference
/8→ 16,777,216 total addresses/16→ 65,536 total addresses/24→ 256 total addresses/30→ 4 total addresses (typically 2 usable)/31→ 2 addresses (point-to-point use)/32→ single host route
Worked Example
If you enter 192.168.50.77/26, the calculator determines that the subnet has 64 total addresses, a network address of 192.168.50.64, and a broadcast address of 192.168.50.127. Usable hosts are typically 192.168.50.65 through 192.168.50.126.
Why Accurate Subnetting Matters
- Security: Proper network segmentation limits blast radius.
- Performance: Right-sized subnets reduce unnecessary broadcast traffic.
- Scalability: Good IP planning makes growth and migrations easier.
- Troubleshooting: Clean subnet boundaries simplify diagnostics.
Common Mistakes to Avoid
Mixing Up /24 and 255.255.255.0
They mean the same thing, but teams often switch formats and lose consistency. Use one style in documentation and include the other as a reference.
Forgetting Reserved Addresses
In most subnets, network and broadcast addresses are not assignable to hosts. That changes only in specific edge cases like /31.
Assigning Overlapping Networks
Overlapping subnets can cause routing confusion and intermittent failures. Always validate new subnet allocations before deployment.
Final Note
This calculator is built for IPv4 planning and education. It gives immediate, practical values that are useful for home labs, enterprise network design, and certification study workflows.